Transmitter Bandwidth Optimization Circuit

1. A microelectronic element, comprising: a transmitter having a frequency response capable of peaking and controllable in accordance with a plurality of operational parameters; a storage operable to store the plurality of operational parameters for controlling the frequency response of the transmitter under each of a plurality of operating conditions corresponding to the plurality of operational parameters; at least one sensor operable to detect one of the plurality of operating conditions; and a control circuit operable in response to a change in the detected operating condition to use one of the stored operational parameters corresponding to the detected operating condition to control the frequency response of the transmitter, wherein said frequency response is represented by a Bode plot for each of the plurality of operational parameters; wherein the plurality of operating conditions comprises values of at least two variables; and wherein the transmitter is operable to transmit data serially over a cable external to the microelectronic element and the at least two variables includes at least one of (a) a length of a cable to which the transmitter is coupled to transmit output and (b) a data transmission rate for transmitting data by the transmitter.

2. A microelectronic element as claimed in claim 1 , wherein the detected operating condition includes a temperature of the microelectronic element.

3. A microelectronic element as claimed in claim 1 , wherein the detected operating condition includes a power supply voltage level supplied to the microelectronic element.

4. A microelectronic element as claimed in claim 1 , wherein the transmitter includes an adjustable peaking element, wherein the control circuit is operable to apply the stored operational parameter to control a peaking function of the adjustable peaking element.

5. A microelectronic element as claimed in claim 1 , wherein the at least two variables include a temperature and a power supply voltage level.

6. A microelectronic element as claimed in claim 1 , wherein the control circuit is operable to determine the operational parameters for the plurality of operating conditions when the transmitter is powered on from an off state.

7. A microelectronic element as claimed in claim 1 , wherein the storage includes a plurality of fusible links.

8. A microelectronic element as claimed in claim 1 , wherein the storage includes non-volatile memory.

9. A microelectronic element as claimed in claim 1 , wherein the at least one sensor includes a temperature sensor and a voltage sensor.

10. A method of operating a transmitter integrated in a microelectronic element, comprising: (a) operating the transmitter and detecting an operating condition under which the transmitter operates; (b) when the detected operating condition changes, retrieving a stored operational parameter from a plurality of stored operational parameters, each stored operational parameter corresponding to an operating condition from among a plurality of different operating conditions; (c) using the retrieved operational parameter to control a frequency response of the transmitter, wherein the frequency response, capable of peaking, is represented by a Bode plot for each of the plurality of stored operational parameters; and (d) repeating steps (a) through (c) while the transmitter is operating, wherein the plurality of different operating conditions comprises values of at least two variables and the transmitter is operated to transmit data serially over a cable external to the microelectronic element and the at least two variables includes at least one of (a) a length of a cable over which the transmitter transmits data and (b) a data transmission rate at which the transmitter is operated.

11. A method of operating a transmitter as claimed in claim 10 , wherein the detected operating condition includes a temperature of the microelectronic element.

12. A method of operating a transmitter as claimed in claim 10 , wherein the detected operating condition includes a power supply voltage level supplied to the microelectronic element.

13. A method of operating a transmitter as claimed in claim 10 , wherein the transmitter includes an adjustable peaking element, and the retrieved operational parameter is used to control a peaking function of the adjustable peaking element.

14. A method of operating a transmitter as claimed in claim 10 , further comprising determining the operational parameters by calibrating a frequency response of a transmitter included in a second microelectronic element under at least some of the plurality of operating conditions.

15. A method of operating a transmitter as claimed in claim 10 , wherein the at least two variables include a temperature and a power supply voltage level.

16. A method of operating a transmitter as claimed in claim 10 , further comprising determining the operational parameters for the plurality of different operating conditions when the transmitter is powered on from an off state.